1. Field of the Invention
The present invention relates to a heating apparatus for performing heat treatment by positioning a substrate on a hot plate and thereafter cooling the substrate at a cooling position adjacent to the hot plate, a heating method, and a coating apparatus using the heating apparatus, and further relates to a storage medium storing a computer program for performing the heating method.
2. Description of the Background Art
A coating and development apparatus applying a resist to a substrate and developing the exposed substrate has been used as an apparatus for forming a resist pattern on a semiconductor wafer (hereinafter, referred to as “wafer”) or a glass substrate for LCD (liquid crystal display) representing the substrate. In this apparatus, a hydrophobic treatment unit for subjecting the surface of the substrate to hydrophobic treatment by bringing the substrate into contact with vapor of a hydrophobic treatment agent while heating the substrate, a heating apparatus for drying a solvent in a resist film or an antireflection coating applied to the surface of the substrate, a heating apparatus for altering quality of the exposed resist film on the surface of the substrate, and the like are incorporated.
The hydrophobic treatment unit or the heating apparatus of such a type (these units or apparatuses are hereinafter simply referred to as “heating apparatus”) serves to heat the substrate mounted on a heating plate, for example, at a temperature around 100° C., and a structure combined with a cooling plate for performing cooling immediately after heating of the substrate for a predetermined time period, namely, for performing what is called rough heat removal, has been known (for example, Japanese Patent Laying-Open No. 2004-235469).
FIG. 12 shows an exemplary structure of a heating apparatus for heating a wafer W representing a substrate. The heating apparatus has a housing 10 including a wafer transfer port 10a and a shutter 10b for opening/closing transfer port 10a, a base 11 provided in housing 10, a hot plate 12 for heating wafer W, and a cooling plate 13 for cooling wafer W, that is movable toward hot plate 12 over base 11. In base 11, a gas supply portion 14 is provided on the front side of hot plate 12 and an exhaust portion 15 is provided on the rear side of hot plate 12.
In a space inside base 11, elevator mechanisms 16, 17 for elevating/lowering pins 16a, 17a are provided. As a result of elevation/lowering of pin 16a by means of elevator mechanism 16, wafer W is delivered between an external substrate transfer mechanism (not shown) introduced in housing 10 and cooling plate 13. In addition, as a result of elevation/lowering of pin 17a by means of elevator mechanism 17, wafer W is delivered between hot plate 12 and cooling plate 13. FIG. 12 shows a lid-like top plate 18 that can be elevated/lowered by means of an elevator mechanism 18a. 
In such a heating apparatus, initially, hot plate 12 is covered with top plate 18 and heated to a prescribed temperature, and in such a state, wafer W is delivered to cooling plate 13. Thereafter, top plate 18 is elevated, cooling plate 13 is introduced between top plate 18 and hot plate 12, and wafer W is delivered from cooling plate 13 to hot plate 12. Then, cooling plate 13 is returned to a position adjacent to hot plate 12, and top plate 18 is lowered to a position slightly above hot plate 12. In this state, by supplying a gas from gas supply portion 14 while performing evacuation through exhaust portion 15, the space between hot plate 12 and top plate 18 is purged for performing prescribed heat treatment. Wafer W that has been subjected to heat treatment is delivered from hot plate 12 to cooling plate 13 after top plate 18 is elevated, thereafter delivered from cooling plate 13 to the not-shown substrate transfer mechanism, and transferred to the next process.
Meanwhile, in this heating apparatus, for example, such a cooling mechanism that a cooling pipe is provided inside or on a lower surface of cooling plate 13 and a coolant is fed through this cooling pipe is provided. Therefore, cooling plate 13 has a thickness around 10 mm. Accordingly, in order to deliver/receive wafer W to/from cooling plate 13, taking into account the thickness of cooling plate 13 and clearance for delivery of wafer W, a gap of at least 10 mm between hot plate 12 and top plate 18 is necessary.
Thus, the conventional heating apparatus has had a large height, because the up/down pin and the elevator mechanism for elevating/lowering wafer W are necessary, the cooling plate is transferred to above the hot plate, or clearance for delivering wafer W between the hot plate and the cooling plate is necessary.
Meanwhile, in order to suppress increase in an occupied area with increase in the size of a substrate such as wafer W, a coating and development apparatus including treatment units such as heating apparatuses arranged in multiple layers has been commercialized. In such a case, if the heating apparatus has a large height, the number of layers cannot be increased.
In addition, elevation/lowering of top plate 18 or delivery of wafer W between cooling plate 13 and hot plate 12 is necessary in the heating apparatus described above, and a time required for such an operation turns out as an overhead time (operation time) not directly relevant to heat treatment, which results in lower throughput.
Though Japanese Utility Model Laying-Open No. 62-017133 describes an apparatus for transferring a substrate by means of wires, it is silent about a method for solving the above-described problems. In addition, if a wafer is directly mounted on the wires, the wafer is contaminated due to adhesion of particles or the like caused by contact between the wafer and the wires, which leads to lower product yield.